Many packaging containers for liquid food are manufactured in so-called portion volumes, intended to be consumed direct from the package. The majority of these packages are provided with drinking straws in a protective envelope which is secured to the one side wall of the packaging container. The packaging containers, which are often parallelepipedic in shape, are manufactured from a laminate with a core of paper or paperboard, with layers of thermoplastics and possibly aluminum foil. On the one wall of the packaging container—most often the top wall—a hole has been punched out in the core layer and this hole is covered by the other layers of the laminate, which makes it possible to penetrate the hole with the drinking straw which accompanies the packaging container, and hereby consume the drink enclosed in the package.
There have long been machines which apply drinking straws in their protective envelopes to packaging containers which are conveyed through the machine. Such a machine, i.e. a drinking straw applicator, is, for example, described in the European Patent Specification EP-1 042 172. The applicator functions in that a belt of continuous drinking straw envelopes with drinking straws is guided in towards and surrounds a drive means. Adjacent the drive means, there are devices for severing the drinking straw belt into individual drinking straws enclosed in a protective envelope, as well as devices for applying the drinking straw to one side wall of the packaging container, the packaging container being advanced on a conveyor through the machine. Prior to the moment of application, the envelope drinking straw is provided with securement points. The securement points may, for example, consist of hot melt, which is molten glue which glues the drinking straw envelope in place and retains it when the glue has hardened. In this applicator the drive means rotates continuously and the device for separating drinking straws is disposed to accompany a part distance of the rotation of the drive means. Also the conveyor is driven continuously, and the device for applying drinking straws is disposed to accompany a part distance of the movement of the conveyor belt.
In ultra high speed production, handling approximately 40 000-50 000 packages/hour, the motions of the components of a straw applicator, in particular motions including considerable accelerations and decelerations, will give rise to substantial strain on the one or more motors involved and considerable vibrations will be created in the mechanics of the machine.
The Swedish patent application No. 1451136-4 describes an ultra high speed straw applicator. This straw applicator is operated to keep an even pitch between packages, and can thereby for example reduce vibrations. However, there are further improvements to be made for even smoother operation.